A prospective study of 93 unicompartmental knee prosthesis emphasises the appearance of radiolucencies under the tibial component.

Background and study aims: Here, we report the presence of radiolucent lines in a consecutive group of 93 partial knee replacements (UKA). Materials and methods: The prospective study was conducted from 2011 to 2019 with a minimum follow-up of two years. Clinical data and radiographs were recorded. Of the 93 UKA, 65 were cemented. The Oxford Knee Score was recorded before and two years after surgery. In 75 cases, the follow-up was conducted at > 2 years. A lateral knee replacement was performed in 12 cases. In one case, a medial UKA with patellofemoral prosthesis was performed. Results: In eight patients (8.6%), a radiolucent line (RLL) underneath the tibia component was observed. In four of these eight patients, RLLs were non-progressive, without clinical implications. In two cemented UKAs, RLLs were progressive and were revised with total knee arthroplasty. Early severe osteopenia of the tibia (zone 1 to 7) in the frontal view was observed in two cementless medial UKA cases. The demineralisation occurred spontaneously five months after surgery. We diagnosed two early deep infections, one of which was treated locally. Conclusions: RLLs were present in 8.6% of the patients. Even in severe cases of osteopenia, spontaneous recovery of RLLs is possible with cementless UKAs.

Pelvic Support Osteotomy; Salvage Procedure in Chronically Dislocated Hips Case Report: Technical Note on the On-lay Bone Positioning of a Lengthening Nail and Review of the Literature.

BACKGROUND: Young patients with a acquired dislocation of the hip with concomitant shortening of the lower limb is a difficult diagnostic problem with few definite treatment options. METHODS: We used the technique, originally described by Ilizarov, with a double femur osteotomy and lengthening the femur. Lengthening was done with a sub muscular placed on-lay femur distraction rod. Distraction of the rod was done by fluid mechanics. After lengthening, the distraction was secured by a parked plate by locking the distal part of the plate. RESULTS: This patient needed a lengthening of 60 mm, distraction time was 36 days with a distraction index of 1.61 mm per day and a healing index of 31.4 days per cm lengthening.We encountered one complication in which an exchange of the plastic feeding tube was needed at 20 days post-surgery. CONCLUSIONS: In the reported case we could improve gait with reduced limping and equalizing her leg length discrepancy.